1. Field of the Invention
The present invention relates to a method for preparing a porous material using nanostructures and a porous material prepared by the method. More specifically, the present invention relates to a method for preparing a porous material using nanostructures by producing nanostructures using a porous template, dispersing the nanostructures in a source or precursor material for the porous material, aligning the nanostructures in a particular direction and removing the nanostructures by etching, and a porous material prepared by the method.
2. Description of the Related Art
Porous materials, through which fluids are allowed to flow, are classified into microporous materials having a pore size of less than 2 nm, mesoporous materials having a pore size ranging from 2 to 50 nm, and macroporous materials having a pore size of more than 50 nm according to the pore size of the porous materials. Of these porous materials, mesoporous materials have a sufficiently large pore size to permit fluids to freely pass therethrough and a relatively large surface area where they are in contact with fluids. Based on these advantages, mesoporous materials have drawn attention as materials for catalysts, catalyst supports, adsorbents, separators and electric double-layer capacitors. Particularly, since nanoporous materials having a mesopore size, which can be synthesized using numerous precursors, can be used in the production of highly functional catalysts, catalyst supports, separators, hydrogen storage materials, adsorbents, photonic crystal bandgap materials, etc., they are currently in the spotlight. Examples of porous materials include inorganic materials, metals, polymers and carbon materials. Of these, carbon materials have superior chemical, mechanical and thermal stability, and are useful in a variety of applications.
However, it is not easy to prepare porous materials having a structure in which pores are connected to each other. It is particularly difficult to control the pore morphology of porous materials. Under these circumstances, methods for controlling the internal structures (e.g., pore size and porosity) of porous materials using templates have been proposed. For example, a proposal has been made on a method for producing porous carbon structures by filling a carbon precursor into a solid porous silica template, carbonizing the carbon precursor under non-oxidizing conditions, and dissolving the silica template in a HF or NaOH solution to remove the template.
In addition, a method for producing porous metal oxide spheres using porous polymer beads as templates has been proposed (Template Synthesis and Photocatalytic Properties of Porous Metal Oxide Spheres Formed by Nanoparticle Infiltration, Chem. Mater. 2004, 16, 2281-2292). This method comprises the step of dipping the porous polymer beads in a metal oxide sol. Since the method has an advantage in that porous materials having a uniform size and a regular lattice arrangement can be prepared, it is widely employed for the preparation of porous materials. According to the method, however, the controllable size of the beads is as large as 100 nm to several micrometers. The method has a limitation in preparing porous material having a pore size of a few to a few tens of nanometers. Moreover, the method has a problem in that the shape of pores cannot be controlled because the polymer beads have a spherical shape.